1. Field of the Invention
The present invention relates to detection and treatment of various temporal integration disorders, affecting certain daily tasks like reading accuracy. More particularly, the present invention concerns estimation of visual attention as opposed to visible persistence and improvement of visual attention in general and reading ability of dyslexic and hyperactive children in particular.
2. Description of the Related Art
Some researches suggest that disorders of reading acquisition in children are related to magnocellular deficit or developmental impediment, see for example U.S. Pat. No. 6,045,515. This hypothesis is supported to some extent by findings that indicate that dyslexics have anomalies in their magnocellular networks, demonstrated by (1) higher contrast thresholds to detect brief patterns, (2) an impaired ability to discriminate both the direction and the velocity of moving patterns, and (3) unstable binocular control and depth localization when compared to normal individuals of the same age. However it should be kept in mind that most of the mentioned evidences were criticized on several grounds by other dyslexia researchers (for review see Hugban 2001).
However, a recent study (Tallal & Merznich 1998) questions whether dyslexic children show a temporal processing deficit, and another study (DeLolo 1996) concludes that the contrast sensitivity functions (CSFs) of dyslexic children are unrelated to their reading ability.
The main claim of those researchers holding the view that dyslexia is related to magnocellular deficit is that dyslexics have longer then normal visible persistence while reading. This assumed to result from the lack of magnocellular inhibitory effect on parvocellular activation. According to this view, the saccadic eye movements between fixations activate, in normal readers, the magnocellular system, which, in turn, suppresses the parvocellular activation initiated by the processing of the text seen at the former fixation.
Due to magnocellular deficit in dyslexics, this inhibitory process is not reliably activated by the short saccades typical in text reading. Thus the transition from eye fixation to the next is accompanied by a masking effect, i.e. visual information gained in a former fixation masks the information gathered in the next or vice versa.
If this assumption was true then watching a text presented on a special display that gives an advantage to longer then normal visible persistence duration could be used to improve dyslexics reading.
Experiments conducted by the inventor with such a display clearly indicated that dyslexics exhibit inferior rather then superior reading of the display texts compared to normal readers. It was also verified that dyslexics were inferior compared to controls in recognition of any stimuli presented by this display. Further investigations indicated that dyslexics' difficulties are related to visual attention deficit that impedes temporal integration of the visual partial signals when they are presented at low frequencies.